Internal combustion engine



Apgil 25, 1933. J. scHAEFFERs INTERNAL GOMBUSTION ENGINE Filed May 24,

Patented Apr. 25 1933 UNITED sTA JOSEPH SCHAEFFERS, OF CAMDEN, NEW JERSEY INTERNAL COMBUST'IQN ENGINE Application ma nay 24, 1030, serial No.

y coversthe exhaust port only, While the other piston covers or uncovers the intake port only. The two pistons in such case can be so connected that one runs ahead while the other lags behind in their` respective cycles so that the exhaust port opens and closes first While the intake port opens and closes llast. In single piston two-cycle engines as a rule the exhaust port opens irst and closes last, so that some of the new charge is bound to escape through the exhaust port before vhaving done its Work. Also it is impossible to supercharge to above atmospheric pressure.

It is one object of the present desi to make it possible to time the opening anrllosing of the intake port to the same extent as with a double piston engine. To effect the best operation the present design provides for the opening of the exhaust port prior to the opening of the intakey port so that the burnt gases may escape without any possibility of their being driven into the incom-' ing mixture. On the other hand, the exhaust port is closed prior to the closure of the intake port, so that supercharging may be effected without escape of the incoming mixture through 4the exhaust openings.

The engine of the present `invention includes a stepped piston of the trunk type in 40 which an extension is provided adapted to reciprocate through a bore aligned with the cylinder. It is a further object of the present invention to provide a removable cap nor. mally covering the open end of the bore in a single piston type engine so as to afford easy access to the intake ports in the extension for cleaning purposes. It is' another object of the present invention to provide suitable means for packingthe extension against escape of gases, the means comprising specili- 455,180, and in Germany` January 4, 1930.

cally a contracting'ring arranged to engage the outer surface of the extension.

Since the engine of the present invention is particularly designed for aeronautical uses, both the piston and cylinderare made of light metal such as aluminum. or an alloy thereof. It is a further object of the invention to provide a'cylinder and piston extension suitably protected against Wear and to protect the bridges of the .exhaust port to resist the temperature of the exhaust gases.

The accomplishment of the above objects Will be apparent from the following descrip-v tion'read in conjunction with the accompanying drawing, in which:y

Fig. 1 is an axial section through the cylinder, piston and associated. elements of a single acting type of two-cycle engine embodying the features of the present invention; and j Fig. 2 is a fragmentary axial `section of a two-cycle double acting engine embodying the features of the invention.

'The engine, which may include any number of cylinders, one of which is illustrated in Fig..1, comprises a cylinder block indicated at 2, in which are formed the various cylinders communicating .with a crank case 4 in which 'rotates the usualcrank shaft 5 provided with cranks 6 to which are .secured connecting rods 8, in turn pivoted Within the trunk pistons 10. Since the cylinders are formed/of alulninum or some light alloy such as the other alloys of aluminum, it is necessary to protect the bores thereof against Wear occasioned by the reciprocation of the-pistons. each cylinder are coated .with chromium or high carbon steel by the spraying method, the coating being, ,for example, .01 inches Accordingly the inner surfaces of thick and thereby affording protection both y.

against Wear andthe heat generated dur-ing the explosions.,4

The piston 10 is of the steppedtype, being provided with an extension 14 coated externally with high carbon steel or chromium by the spraying method similarlyto the interior of the cylinder. The extension 16 reciprocates in a bore in the cylinder head formed lby a sleeve 18, Which/1s provided With an annular shoulder 19 engaging a suitable annular step in the cylinder head, the sleeve being secured in the head by means of a nut 24threaded on its outer end. Threaded on the inner end of the sleeve 18 is an annular member 22. In the present instance the sleeve-is shown as provided with a recess adapted-to receive a contracting ring 20 arranged to engage' the outerlcoated surface of the 4extension 14. The arrangement is such that when the annular member 22 is moved to its innermost limit of movement,- there is axial clearance in the opening receiving the ring suilicient to permit contraction of the ring into tight engagement with the extension. It will be understood that instead of providing the recess in the sleeve 18, it might be provided in the annular member 22 or in both. f'

l connecting rod 8.

' sion 14. The sleeve 34 is connected by a link 36 with the pivot 38 of a side extension of the The upper end of the cylinder is provided with a suitable opening 40, or series of such openings, arranged to receive a spark plug or series of spark plugs. The cylinder is arranged-to be either water cooled by water in a jacket, as shown, or air cooled, in which case it is provided with suitable annular cooling fins.

An exhaust port includes a series of open-v ings 42 separated by the usual bridges and arranged to be uncovered by the piston at the outer ends of its strokes. The cylinder is also provided with a fuel admission port comrising a series of openings 44 arranged to e uncovered by the piston atthe inner ends of its strokes.

vAs illustrated in Fig. 1, the piston is at the inner e'nd of its stroke and it may be assumed that the mixture has just been exploded. The crank case is now charged with combustible mixture and communication between the crank case and cylinder through the extension is closed by reason of the position of the exten-` sion 14 within the sleeve 18.

As the shaft moves in the direction of the arrow in Fig. I, the piston moves downwardly. During this movement the pivotal point 38 of the link 36 assumes, relatively to the piston, the position a, due to the angularity of the connecting rod. When this condition is reached the sleeve 34 will be moved upI al suilicient distance to cover thelower series of openings 32. The piston, during its outer stroke, first closes the mixture admission port 44 and then as it approaches outer dead center, uncovers the exhaust ports 42. At the time the piston 'begins to uncover the exhaust ports, the

lowerl ends of openings 32 will pass below the sleeve 18 but the intake port will not then be opened to the cylinder, since the sleeve 34 covers vthe lower series of openings. Ac-

cordingly the exhaust port 42 is open approximately 15 prior to the opening of the intake port by the passage of the lower ends of the openings 30 below sleeve 18. There is thereby given assurance that the exhaust gases have dropped to substantially at1nos pheric pressure prior to the opening of the intake port.

As the intake port opens, the compressed mixture from the crank case passes into the cylinder. On the reverse stroke it will be noted that the angularity of the connecting rod causes it to slope in the opposite direc- 32 move above the lower end of the sleeve 18 and are thereby closed.` After the piston opens the admission port 44 a new supply of mixture is drawn into the crank case by reason of the vacuum created during the inward movement of the piston.

As is usual in the case ofengines of the general type illustrated, because of the ex-y tension 14, the displacement of the piston with respect to mixture inthe crankcase is greater than the displacement in the working portion of the cylinder. Accordingly,

supercharging is eil'ected in the present englne because of the early closure of the exhaust port compared with the intake port whereby the increased pressure due to the di'erential displacements is maintained. In

engines of prior design this pressure was lost because of the escape of gases through the exhaust port, such escape being very materially reduced in the present design, and being negligible when the engine is operating at full speed.

In order to protect the bridges between ,the openings of the exhaust port against the destructive eil'ect ofthe hot gases, their walls are covered with a suitable thickness of the high carbon steel or chromium by spraying in the same way that the coating is applied to the cylinder walls.

It `will be noted that in the inner dead center position of the liston 10 the intake openings 30 and` 32 project beyond the upper end of the sleeve 18. If the cap 26 is removed, the openings are readily accessible from the exterior of the engine so that they may be cleaned of carbon or oil coal which has accumulated thereon and which is liable to form as a result of too much or unsuitable oil being mixed with the fuel.

Therehas been described above the application of the features of the ,'nvention to a single acting type of enginefln Fig. 2

the invention is shown as applied to a double acting engine in which there are provided two cylinders 46 and 48 coated on their interior surfaces with a wear resisting metal and in which reciprocate the pistons 50 and 52 connected by the extension member 54. The piston 50, which is adjacent the crank case, is connected to the crank on the crank shaft by connecting rod 56.

Al separating memberl 58 is located within the extension 54. Through this separating member reciprocates a rod 60 carrying sleeves 62 and 64 arranged to cooperate withthe intake port openings 66 land 68 in the same manner-that sleeve 34 in Fig. 2 cooperates with its corresponding intake port openings. The rod 60 is connected by the link 70 with the lateral extension 72 of the connecting' rod 56.

In the operation of this double acting engine with the crank shaft rotating in a` counterclockwise direction, it will be obvious that the cycle of operation in each of the cylinders is similar to that described above in connection with a single acting engine. 'It will be noted that the phases .of operation of the two sleeves 62 and 64 cooperating with the intake ports are properly timed through the medium of a single connection `to the connecting rod 56.

What I claim and desire to protect-,by Letters Patent:

1. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the cylinder, a shaft, connections between the piston and shaft-for driving the latter,a hollow extension carried by the piston, providing communication between its opposite sides, and reciprocating in a bore aligned 'with the cylinder, said extension having an intake port arranged to communicate with the cylinder when the piston is at the outer end of its stroke, and the cylinder having an exhaust port arranged to be uncovered by the piston at the outerend of its stroke, and means for delaying the opening of the intake port until after the opening of the exhaust port.

2. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the cylinder, a shaft, connections between the piston and shaftfor driving the latter,

a hollow extension carried by the piston,pro viding communication between its opposite sides, and reciprocating in a bore aligned with the cylinder, said extension having an intake port arranged'tocommunicate with the cyllnder when the piston is at the outer end of its stroke, and the cylinder havin an exhaust port arranged to be uncovered y the piston at the outer end of'i'ts stroke, and means for delaying the closing of the intake port until after the closing of the exhaust port.

l3. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the cylinder, a shaft, connections between the piston and shaft for driving the latter, a hollow extension carried by the piston, providing communication between its opposite sides, and reciprocating ,in a bore aligned with the cylinder, said exten-I sion having an intake port arranged to communicate with the cylinder when the piston is at the outer end of its stroke, and the cylinder having an exhaustl port arranged to be uncovered by the piston at-the port until after the respective opening and closing of the exhaust port.

4. A two-cycle internal combustion engine comprising a cylinder, apiston movable in the cylinder, a shaft, connections between the-piston and shaft for driving the latter, a hollow extension carried by the piston, providing communication between its opposite sides,` and reciprocating in a bore aligned with the cylinder, said extension having an intake port arranged to communicate with the cylinder when the piston is at the outer end of its stroke, and the cylinder having an exhaust port arranged to be uncovered by the piston at the outer end of its stroke, and means for delaying both the openingl and closing of the intake port until after the respective opening and closing of the exhaust port, said means including 'a sleeve moving vwithin the extension and arranged to close the intake port.

5. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the cylinder, a shaft, connections between the piston and shaft for driving the latter, said connections including a connecting rod, a hollow extension' carried by the piston, providing communication between its o posite sides, and reciprocating in a ore aligned with the cylinder, said extension having an intake port arranged to communicate with the cylinder when'the piston is at the outer end of its stroke, and the cylinder having an exhaust port arranged to be uncovered by the piston atfthe outer end of its stroke, and means for delaying both the opening and closing of the intake'- port until.

gine comprising a c linder, a piston movable in the cylinder, a ollow extension carried by the piston, a sleeve providing a bore aligned with the cylinder and in which the extension reciprocates, and an annular member adapted to be threaded to the sleeve in the direction of its axis, the sleeve and annular member providing a recess adapted to receive a contracting ring adapted to engage the extension. v

7. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the c linder, a shaft, connections between the-p1ston and shaft for driving the latter, a hollow extension carried by the piston, providing communication between its opposite sides, and reciprocating in a bore laligned with the cylinder, said extension having an intake port arranged to communicate with the` cylinder 'when the piston is at the outer end of its stroke, and the cylinder having an exhaust port arranged to be uncovered by the piston at the vouter end of its stroke, and automatic means within the extension of the piston arranged to delay the closing of the intake port until after the closing of the exhaust port.

8. A two-cycle internal combustion engine comprising a cylinder, a piston movable in the cylinder, a shaft, connections between the piston and shaft for driving the latter,

a hollow extension carried by the piston, pro- A viding communication between its opposite sides, and reciprocatlng 1n a bore allgned with the cylinder, said extension having a main intake port and an auxiliary intake port, the former being opened and'closed solely by relative movements of the extension and bore within which it reciprocates,

the cylinder having an exhaust port arranged to be uncovered by the piston at the outer end of its stroke, and automatic means within the extension of the piston for maintaining the auxiliary intake port open until after the closing of the exhaust port.

Y In testimony of which invention, I .have hereunto set my hand at Camden, New Jersey, on this 22nd day of May, 1930.

JOSEPH SCHAEFFERS. 

